Non-wettable antibacterial thin film: PS/Aloe vera and PS/Acalypha indica

Abstract

The water and liquid repelling materials due to their low surface energy and specific nanometer and micrometer scale roughness have particular interest due to the great variety of potential applications ranging from self-cleaning surfaces to microfluidic devices. Natural plant-based polymer hydrophobic coatings have several engineering and biomedical applications. In this study, natural plants such as Aloe vera and Acalypha indica were used for preparation of polystyrene hydrophobic film by the dip-coating method. The effects of Aloe vera and Acalypha indica extract on the morphological, structural, optical and antibacterial properties of as-prepared polystyrene thin films were studied. FTIR spectra were carried out to ascertain the presence of functional groups in the prepared polymeric film. Contact angle measurement showed that the PS/ Aloe vera has higher anti-wetting property (CA = 112°) compared to PS/ Acalypha indica (CA = 104°), which could be confirmed by the surface morphology analysis. Furthermore, the effective antibacterial activity against Klebsiella pneumoniae and Staphylococcus aureus was compared by agar-well diffusion method. The observed result reports, PS with Aloe vera film exhibit higher hydrophobic with antibacterial activity compared to PS with Acalypha indica film. In addition, the PS/ Aloe vera coated cotton maintained their repellent properties against various liquids for 10 h, while PS/ Acalypha indica coated cotton exhibit anti-wetting property for 4 h. These findings open up new avenues for the preparation of hydrophobic film for various biomedical applications.

The Characterization of the Hydrophobic Surface of Nanocomposites Aloe vera/PS for Antimicrobial Pathogens

“…The FTIR results of this study are in accordance with Seifunnisha et al ( 2021) and Chauhan and Kumar (2020) where the FTIR spectra of Aloe vera thin films have also been studied by Seifunnisha et al (2021) where the dominant functional group was analyzed in the range 4000 cm −1 -400 cm −1 , there is a peak at 3026 cm −1 and 752 cm −1 correspond to C-H stretching. The symmetric and asymmetric vibrations of -CH2 are associated with the vibration bands at 2850 cm −1 and 2926 cm −1 .…”

“…Along with that, the structure of the nanoparticles also plays a major role in the antibacterial properties because the morphological differences in the nanocomposite samples also add to the higher antibacterial activity. According to Seifunnisha et al (2021) Measurement of the contact angle can prove that the thin layer exhibits non-wettable properties which are also confirmed by surface roughness analysis, then the Nanocomposite Aloe vera/PS surface shows potential antibacterial activity against pathogens, where Nanocomposite Aloe vera/PS shows excellent bactericidal activity due to the presence of a large number of phytochemicals such as alkaloids, flavonoids, phenolic compounds and terpenoids.…”

“…The vibrational band at 1805 cm −1 is caused by the C=O characteristic which indicates the presence of a carbonyl group in the Aloe vera sample. The C=C vibrations of the PS aromatic ring appear at 1598 cm −1 (Seifunnisha et al, 2021) . According to Chauhan and Kumar (2020) the FTIR spectra of Aloe vera extract have a C=C vibration band at 1500 cm −1 and a C=O vibration band at 1700 cm −1 indicating the presence of aromatic rings and flavonoids in Aloe vera.…”

“…Hydrophobic thin films sourced from Aloe vera are one of the efforts to produce coating materials for anti-pathogenic microorganisms by adding polystyrene polymers as a matrix (reinforcer) (Seifunnisha et al, 2021) . The hydrophobic coating has the characteristics of being effective in self-cleaning and having a contact angle of >90 • (Ratnawulan et al, 2020;Fauzi, 2019;Fauzi and Putri, 2020).…”

“…Based on previous research, a layer of Aloe vera/Polystyrene (AV/PS) has been successfully prepared by producing a diameter of 113 mm inhibition area for pathogenic microorganisms and a contact angle (WCA) of 112 • applied to cotton using the dip coating method (Seifunnisha et al, 2021;Dastan et al, 2016;Tang and Yan, 2017;Ho et al, 2018). However, this study has a drawback where the value of the contact angle can still be increased.…”